Tank trucks are widely used as emergency vehicles for transporting water to remote locations to battle a fire where local access to water may not be adequate or available. Fire tanker trucks used for carrying water commonly do so by drawing a supply of water from a local lake, river, or other body of water into the tank by vacuum, and then rushing to the scene of the fire where the water is unloaded into a temporary structure, the truck thereafter returning for additional water. In such service, the truck is operated at high speeds, frequently over uneven terrain, with partial loads, and with frequent sudden braking and turning. Since the tanks carried by such trucks are normally not completely filled, sudden surges of the water held therein are common.
Water has a liquid density of about 8.3 pounds per gallon, and a load weight of about 6 tons is typical for emergency tankers. The momentum of such loads, i.e., the product of the load's mass times its velocity, can be extremely high. As time is of the essence for emergency vehicles, the vehicles must travel quickly to their destination, often making quick starts, stops and abrupt turns. For example, in an abrupt stop of the emergency vehicle, the inertial forces created by the sudden shifting of the load can have a serious destabilizing effect on the vehicle. Such forces, including others generated by violent movements of the vehicle encountered in high speed operation, particularly over uneven surfaces, make it difficult to exercise control over the vehicle, with attendant risks of damage to the vehicle and its load, as well as injury to the driver and others who may be involved in the incident.
To avoid such destabilization, the tank can be filled to capacity; however, it is not always possible or desirable to carry full loads. An alternative expedient involves the installation of baffles in the interior of the tank positioned at right angles to the anticipated movement of the vehicle carrying it. Such baffles, in effect, form compartments within the tank, limiting the distance that the tank's cargo can shift, thus minimizing the build-up of liquid velocities, and thereby ameliorating the destabilizing effects that would otherwise occur. An example of such baffles is presented in co-owned U.S. Pat. No. 4,789,170, herein incorporated by reference.
While relatively successful, the baffles have several limitations. During turns, the transverse baffling has limited effect on the side-to-side movement of the water commonly referred to as sloshing. Sloshing also can result in destabilization of the vehicle. Another problem is related to the servicing of the tanks. It is often required that the interior of the tanks be inspected, cleaned, and/or treated with a protective coating to prevent corrosive effects of the water. In order to allow access, the baffling must have a cutout large enough for a person to pass to the compartments of the tank formed by the baffles. The cutouts allow flow of the water between compartments during operation of the tanker. The larger the cutout, the less effect the baffles will have in preventing destabilization of the vehicle.
The foregoing illustrates limitations known to exist in present baffle systems for tank trucks, especially for emergency vehicles. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.